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			DecTree - Help
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				DecTree - Help
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								<h2>
									Contents
								</h2>
							</div>
							<ul>
								<li class="toclevel-1 tocsection-1">
									<a href="#Introduction">
										<span class="tocnumber">
											1
										</span>
										<span class="toctext">
											Introduction
										</span>
									</a>
									<ul>
										<li class="toclevel-2 tocsection-2">
											<a href="#Decision_trees">
												<span class="tocnumber">
													1.1
												</span>
												<span class="toctext">
													Decision trees
												</span>
											</a>
										</li>
										<li class="toclevel-2 tocsection-3">
											<a href="#ID3">
												<span class="tocnumber">
													1.2
												</span>
												<span class="toctext">
													ID3
												</span>
											</a>
										</li>
									</ul>
								</li>
								<li class="toclevel-1 tocsection-4">
									<a href="#The_application">
										<span class="tocnumber">
											2
										</span>
										<span class="toctext">
											The application
										</span>
									</a>
									<ul>
										<li class="toclevel-2 tocsection-5">
											<a href="#General">
												<span class="tocnumber">
													2.1
												</span>
												<span class="toctext">
													General
												</span>
											</a>
										</li>
										<li class="toclevel-2 tocsection-6">
											<a href="#The_menu_bar">
												<span class="tocnumber">
													2.2
												</span>
												<span class="toctext">
													The menu bar
												</span>
											</a>
										</li>
										<li class="toclevel-2 tocsection-7">
											<a href="#The_table_view">
												<span class="tocnumber">
													2.3
												</span>
												<span class="toctext">
													The table view
												</span>
											</a>
										</li>
										<li class="toclevel-2 tocsection-8">
											<a href="#The_automatic_tree">
												<span class="tocnumber">
													2.4
												</span>
												<span class="toctext">
													The automatic tree
												</span>
											</a>
										</li>
										<li class="toclevel-2 tocsection-9">
											<a href="#The_interactive_tree">
												<span class="tocnumber">
													2.5
												</span>
												<span class="toctext">
													The interactive tree
												</span>
											</a>
										</li>
										<li class="toclevel-1 tocsection-11">
									<a href="#Further_information">
										<span class="tocnumber">
											3
										</span>
										<span class="toctext">
											Further information
										</span>
									</a>
									<ul>
										<li class="toclevel-2 tocsection-12">
											<a href="#Format_of_the_input_files">
												<span class="tocnumber">
													3.1
												</span>
												<span class="toctext">
													Format of the input files
												</span>
											</a>
											<ul>
												<li class="toclevel-3 tocsection-13">
													<a href="#CSV_files">
														<span class="tocnumber">
															3.1.1
														</span>
														<span class="toctext">
															CSV files
														</span>
													</a>
												</li>
												<li class="toclevel-3 tocsection-14">
													<a href="#Excel_workbooks">
														<span class="tocnumber">
															3.1.2
														</span>
														<span class="toctext">
															Excel workbooks
														</span>
													</a>
												</li>
											</ul>
										</li>
									</ul>
								</li>
									</ul>
								</li>
							</ul>
						</td>
					</tr>
				</tbody>
			</table>
			<h2> 
				<span class="mw-headline" id="Introduction">
					Introduction
				</span>
			</h2>
			<p>
				The application 'DecTree' creates decision tree with an algorithm that decides the next attribute through
				the principle of entropy.
			</p>
			<h3>
				<span class="mw-headline" id="Decision_trees">
					Decision trees
				</span>
			</h3>
			<p>
				Decision trees are used to calssify data from the real world. So called 'attributes' describe a feature
				of the world. The attribute 'weather' for example could have the values 'sunny', 'overcast' and 'rainy'.
				A combination of values of different attributes is called an 'object'. The goal of the decision tree
				is to classify those objects into so called 'goal attributes'. If a learning set for example contains
				the attributes 'weather', 'temperature', 'humidity' and 'play tennis' (where the last one is the goal
				attribute) the decision tree tries to classify the objects based on their values into the goal attribute.
			</p>
			<h3>
				<span class="mw-headline" id="ID3">
					ID3
				</span>
			</h3>
			<p>
				ID3 (Iterative Dichotomiser 3) is an iterative algorithm used to select attributes when creating decision
				trees. It calculates the weighted entropy (in other words: the 'measure' of unorder) for each so far
				unused attribute. The lower the weighted entropy, the better the learning set is classified by the attribute.
				The learning set is split on the attribute with the lowest weighted entropy. For each resulting subset
				(which number is as high as there where distinct values in the attribute) a tree node is created and the
				entropy of the next attribute is calculated.
			</p>
			<h2>
				<span class="mw-headline" id="The_application">
					The application
				</span>
			</h2>
			<h3>
				<span class="mw-headline" id="Genral">
					General
				</span>
			</h3>
			<p></p>
			<a class="image">
				<img alt="general.jpg" src="helpFiles/general.png" width="778" height="500" />
			</a>
			<p></p>
			<p>
				The application is structured into several areas: The menu bar, the table view, the automatic tree, the
				interactive tree and the rule view. The menu bar contains several items to import and export files or to
				edit certain settings. In the table view the data that are to be transformed into a decision tree are
				stored. The automatic tree view automatically creates a tree from the given data. The interactive tree view
				the user can create a custom tree. The rule view display the rule of the current decision tree. The user
				can input an object and the application will forecast its class.
			</p>
			<h3>
				<span class="mw-headline" id="The_menu_bar">
					The menu bar
				</span>
			</h3>
			<p>
				The menu bar is separated into three parts: 'File', 'Settings' and 'Help'.
			</p>
			<P>
				The 'File' menu:
			</p>
			<ul>
				<li>
					Import...: Opens a 'Comma Seperated Values' file (.csv) or Excel workbook (.xls, .xlsx). The opened
					file will be inserted into the table view.
				</li>
				<li>
					Export...: Saves the data in the table view to a 'Comma Seperated Values' file (.csv) or Excel
					workbook (.xls, .xlsx).
				</li>
				<li>
					Exit: Closes the application.
				</li>
			</ul>
			<p>
				The 'Settings' menu:
			</p>
			<ul>
				<li>
					Language: Each supported language has its own subitem here. Text in the application will be automatically
					updated upon language change.
				</li>
				<li>
					Preferences: Opens a dialog where several settings can be made.
				</li>
			</ul>
			<p>
				The 'Help' menu:
			</p>
			<ul>
				<li>
					Help: Opens this help window.
				</li>
			</ul>
			<h3>
				<span class="mw-headline" id="The_table_view">
					The table view
				</span>
			</h3>
			<p>
				The table view displays the data from which the decision trees will be generated. A column represents an
				attribute. The column with the yellow background is the goal attribute. With the items in the toolbar several
				actions can be taken:
				<ul>
					<li>
						Add attribute: Adds a new attribute with the supplied name to the table.
					</li>
					<li>
						Remove attribut: Removes the selected attribute from the table.
					</li>
					<li>
						Add object: Adds a new empty object to the table.
					</li>
					<li>
						Remove object: Removes the selected object from the table.
					</li>
					<li>
						Select goal attribute: Sets the goal attribute to the selected attribute.
					</li>
					<li>
						Reset table: Removes all objects and attributes from the table:
					</li>
				</ul>
				With a double click on an object its values can be edited. In order to create a decision tree from the table data
				the table must be complete. A table is complete when at least one object exists, the goal attribute is not empty,
				at least one attribute besides the goal attributes exists and each cell contains a value.
			</p>
			<h3>
				<span class="mw-headline" id="The_automatic_tree">
					The automatic tree
				</span>
			</h3>
			<a class="image">
				<img alt="Tree view.jpg" src="helpFiles/tree_view.png" width="850" />
			</a>
			<p>
				The from the table data automatically created tree is displayed here. The nodes are displayed hierarchically with
				the root on top down to the bottom (top down layout). Decision nodes are displayed green, leafs blue and selected
				nodes red (standard, can be changed). A node contains the following information:
				<ul>
					<li>
						Attribute/Result: The attribute (or the result if it is a leaf) that this node represents.
					</li>
					<li>
						Object count: The number of objects this node contains.
					</li>
					<li>
						Entropy: The entropy of the table contained by this node.
					</li>
					<li>
						The number of objects that belong to each class this node contains.
					</li>
				</ul>
				The lines hold the value of the attribute through which the next node was reached. On the right side the tree is
				displayed with a file tree layout. Nodes can be selected there (the selected node will be marked in the top down
				layout accordingly). The table below that displays the table contained by the selected node. The tree view is not
				automatically updated when data changes in the table view. Instead the user can request the creation of a new tree
				based on current table data with the refresh button in the tool bar.
			</p>
			<h3>
				<span class="mw-headline" id="The_interactive_tree">
					The interactive tree
				</span>
			</h3>
			<p>
				The from the table data interactively created tree is displayed here. The layout is similar to that of the automatic
				with the exception that the tree is not created automatically. A click on the refresh button resets the tree so that
				only one empty node is displayed. It is possible to set an attribute on a selected node by clicking on the 'Edit
				attribute' button. While selecting the attribute the weighted entropy of each is displayed. When an attribute is
				selected the application will automatically create empty nodes (or leafs, if the leaf conditions are met). A new
				attribute can be set on those empty nodes.
			</p>
			<h2>
				<span class="mw-headline" id="Further_information">
					Further information
				</span>
			</h2>
			<h3>
				<span class="mw-headline" id="Format_of_the_input_files">
					Format of the input files
				</span>
			</h3>
			<p>
				The application allows loading and saving of CSV files and Excel workbooks (XLS and XLSX).
			</p>
			<h4>
				<span class="mw-headline" id="CSV_files">
					CSV files
				</span>
			</h4>
			<p>
				The predefined separator is the ',' (comma) but this can be changed in the settings. The values in the first line are counted as
				attribute names. As a result of that the input file must contain at least one line. The first line must not contain gaps. All other
				lines are counted as objects. Objects don't have to be complete, but the number of values must match the number of attributes.
			</p>
			<h4>
				<span class="mw-headline" id="Excel workbooks">
					Excel workbooks
				</span>
			</h4>
			<p>
				Both file versions (XLS and XLSX) are supported. While reading the file only the first sheet is searched for data. The image
				below describes which cells areread.
			</p>
			<a class="image">
				<img alt="Tabellenbereich einer Excel Arbeitsmappe" src="helpFiles/excel_table.png" />
			</a>
			<p>
				Firstly the first row which contains a value is searched. The values of that row are counted as attribute names (underlined in blue).
				That row must not contain gabs but there may be any number of empty cells before the first and after the last value. The remaining rows
				are read as objects. Values not within the bounds of the attribute row are ignored (red border). 
			</p>
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